JP2006168017A - Sheet for inkjet recording - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a sheet for inkjet recording which enables decoration of a floor surface with a printed image when it is stuck on the floor surface by the medium of an adhesive layer after printing and which causes no blur of the image of an ink accepting layer, nor a peel in this layer, even when water or the like spilling on a floor comes into contact with the peripheral end part of a printed sheet layer, in the case when the sheet having an excellent printability and particularly having a water-resistant and transparent base, for instance, is used. <P>SOLUTION: As to constituents of the ink accepting layer, 50-100 pts.mass of inorganic pigment and 2-20 pts.mass of water-soluble magnesium salt (in terms of an anhydrous salt) are added to 100 pts.mass being the total of 55-75 pts.mass of water-insoluble resin which includes 60-30 mass% of the water-insoluble resin including 40-70 mass% of a polyurethane resin as a requisite constituent, and of 25-45 pts.mass of water-soluble resin which consists of 30-70 mass% of polyvinyl alcohol and/or modified matter thereof and 70-30 mass% of polyvinylpyrrolidone. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

The present invention relates to an ink jet recording sheet having excellent printability, and more particularly to an ink jet recording sheet in which an ink receiving layer having excellent printability and water resistance is laminated on a substrate surface.

Inkjet printing method is a method that prints monochrome or color images on the surface of a recording sheet at high speed by ejecting fine droplets of ink containing a coloring material composed of a dye or pigment from the nozzle toward the surface of the recording sheet. It is. Ink used for inkjet printing is usually water-based ink in which water is the main component and a small amount of alcohol is added to it from the viewpoint of safety and recording characteristics. Under such circumstances, a recording material conventionally used for ink jet recording is one in which an ink receiving layer for receiving fine ink solution particles is provided on the surface of paper or a plastic film.

Ink containing a hydrophobic resin and a pigment as the above-mentioned receiving layer in order to improve curling due to expansion, shrinkage, etc. that occurs when printing on the ink receiving layer, leaving the recording material in a humid place or drying. As a solvent used in the coating liquid of the absorbent layer to provide a receiving layer (Patent Document 1), using a general general-purpose material and providing a bulky, oil-absorbing and water-absorbing coating absorbing layer Use a mixed solvent of a good solvent and a poor solvent for the binder and use a good solvent whose boiling point is lower than that of the poor solvent (Patent Document 2), and record a printed image on the base film by an ink jet method In a recording sheet provided with an ink receiving layer for the purpose, a crosslinking agent that selectively crosslinks polyvinyl alcohol, polyvinylpyrrolidone, and polyvinyl alcohol on the ink receiving layer , Polyvinyl alcohol-polyester copolymer and a cationic resin are added to improve water resistance without impairing ink absorbability, and when laminating immediately after printing, the swelling rate of the coating film due to ink and the fixability of the ink Has been proposed (Patent Document 3) and the like.
JP 08-258411 A Japanese Patent Application Laid-Open No. 08-230174 JP 2001-113188 A

  Each of the above proposals is an improved method for producing an inkjet recording material for general use. For example, the surface of a printed material obtained by inkjet printing an image on an inkjet recording material using a water-resistant film as a base sheet. If a double-sided pressure-sensitive adhesive sheet is bonded to each other, or an adhesive layer is applied by some other method and applied to the floor via these adhesive layers, water spilled on the floor or water during floor cleaning will be printed. May come into contact with the peripheral edge of the. In such a case, water permeates into the ink receiving layer and the image is often blurred or peeled off at the ink receiving layer.

  The present invention overcomes the above-mentioned problems and specifically aims at improving the edge water penetration prevention property of the ink receiving layer of an ink jet recording sheet. In particular, a water-resistant substrate is used as a substrate sheet. In this case, for example, when affixed to the floor via an adhesive layer formed by laminating a double-sided adhesive sheet on the surface of the printed material, water spilled on the floor or water during floor cleaning may be The ink receiving layer does not substantially penetrate water into the ink receiving layer even when it comes into contact with the portion (hereinafter referred to as edge water penetration preventing property), and therefore does not cause image bleeding or peeling in the ink receiving layer. An ink jet recording sheet is provided.

That is, the present invention relates to a water-insoluble resin in which an ink receiving layer is provided with an ink receiving layer on a base material sheet, and the ink receiving layer is composed of 40 to 70% by mass of a polyurethane resin as an essential component. Inorganic with respect to 100 parts by mass of 55 to 75 parts by mass and 25 to 45 parts by mass of water-soluble resin containing 30 to 70% by mass of polyvinyl alcohol and / or a modified product thereof and 70 to 30% by mass of polyvinylpyrrolidone. An ink jet recording sheet comprising 50 to 100 parts by mass of a pigment and 2 to 20 parts by mass (in terms of anhydrous salt) of a water-soluble magnesium salt.

In the ink jet recording sheet of the present invention, the ink receiving layer formed on the surface of the base sheet has water-soluble polyvinyl pyrrolidone (hereinafter abbreviated as PVP) and polyvinyl alcohol and / or a modified product thereof (hereinafter abbreviated as PVA or the like). And a water-insoluble resin containing a water-insoluble polyurethane resin as an essential component, an inorganic pigment, and a water-soluble magnesium salt in a balanced manner, and a printed matter (hereinafter referred to as a printing sheet) on which an image is inkjet printed, Excellent printability. And, in particular, when a water-resistant base sheet is used as the base sheet, it is applied to the surface of the printing sheet, for example, via a pressure-sensitive adhesive layer formed by laminating a double-sided pressure-sensitive adhesive sheet. Even when water spilled on the floor or water at the time of floor cleaning comes into contact with the peripheral edge of the printing sheet, it substantially blocks water from penetrating from the edge of the ink receiving layer to the center (that is, , Edge water penetration prevention). The reason for this is not clear, but PVA or the like at the peripheral edge of the ink receiving layer sandwiched between the two water-resistant layers absorbs water and swells itself, and the water-insoluble polyurethane resin component coexisting with PVA and the like It is presumed that PVA or the like is denatured by the interaction and further prevents water from penetrating. Accordingly, since water does not permeate into the central portion, bleeding of the image of the ink receiving layer and peeling of the ink receiving layer do not occur.

  The ink jet recording sheet of the present invention comprises an ink receiving layer formed on the surface of a substrate sheet.

  Examples of the base sheet include polyethylene terephthalate, polypropylene, polyvinyl chloride, polystyrene, polyvinyl chloride, polymethyl methacrylate, polyethylene and polycarbonate films, foam films thereof, or calcium carbonate or oxide. Examples thereof include plastic films such as films containing pigments such as titanium and pearl pigments, pulp papers, synthetic papers, non-woven fabrics, textiles, and those on which other coating layers are further formed. .

The thickness of the base sheet is not particularly limited as long as it can be supplied to a printing press and can be printed. Depending on the function of the printing press, there is no flexibility, and the thickness is 2 mm or more. Although it may be, it is 25-1000 micrometers normally, and is 50-250 micrometers practically. Moreover, in order to improve the adhesiveness with the ink receiving layer formed on the surface of the substrate sheet, corona discharge machining or an anchor coat layer can be provided on the surface of the base sheet, if necessary.

In addition, after printing on the inkjet recording sheet of the present invention, a pressure-sensitive adhesive layer is formed on the surface by bonding, for example, a double-sided pressure-sensitive adhesive sheet, and the floor surface decoration is carried out by applying to the water-resistant floor surface via this pressure-sensitive adhesive layer. In the case of use, the base sheet is water-resistant and transparent, and the surface opposite to the surface on which the ink receiving layer is laminated (the surface that becomes the walking surface) is hard-coated. Those are preferred. These substrate sheets may be either a high-gloss type or a matte type, but the high-gloss type can better enhance the vividness and contrast of the image. Such a hard coat-treated substrate sheet is not particularly limited, but as a commercial product, Ray Hyper VC01, VN01 (trade name, which is a polyester film coated with a hard coat layer developed exclusively for flooring materials). Tokyo Nakai Shoji Co., Ltd. distributor).

The ink receiving layer is formed by applying an ink-jet receiving layer coating solution containing a water-insoluble resin, a water-soluble resin, an inorganic pigment, and a water-soluble magnesium salt to the surface of the substrate sheet and drying it.

The water-insoluble resin is composed of a water-insoluble resin containing a urethane-based resin as an essential component, and 55 to 75 of the total resin content of 100 parts by mass of the water-soluble resin and the water-insoluble resin constituting the ink receiving layer. It occupies part by mass, preferably 60 to 70 parts by mass, and is usually blended in the form of an aqueous emulsion with respect to each ink-jet receiving layer coating solution.

The polyurethane-based resin is used in combination to improve the ink permeability of the ink receiving layer by modifying PVA or the like by interaction with PVA or the like. The aqueous polyurethane resin emulsion is not particularly limited, but among them, a polyurethane resin emulsion containing a polycarbonate chain in the molecule, a polyurethane resin emulsion containing a polycarbonate chain and a polyester chain in the molecule, and a polycarbonate chain in the molecule. Preferred examples include polyurethane resin emulsions containing sulfonic acid groups. These polyurethane resin emulsions can form a practical film without aging. As such a polyurethane resin emulsion, it is preferable to select a polyurethane resin emulsion having as little emulsifier content as possible in view of the strength of the formed film and water resistance.

Each of the above polyurethane resin emulsions can be produced by a known production method. Specifically, for example, the above-mentioned polyurethane resin emulsion containing a polycarbonate chain is produced by reacting a polyol containing a polycarbonate chain (hereinafter referred to as polycarbonate polyol) with a diisocyanate in a solvent and then emulsifying it. be able to.

In addition, the polyurethane resin emulsion containing a polycarbonate chain and a polyester chain in the molecule described above reacts a polyol containing a polycarbonate chain, a polyol having a polyester chain (hereinafter referred to as a polyester polyol), and a diisocyanate in a solvent, Thereafter, a method of producing by emulsification, or first, a polycarbonate polyol and diisocyanate are reacted in a solvent and then emulsified, and a polyester polyol and diisocyanate are reacted in a solvent and then emulsified, It can manufacture by the method of manufacturing by mixing these.

In addition, the polyurethane resin emulsion containing a polycarbonate chain and a sulfonic acid group in the molecule is obtained by reacting a polyol containing a polycarbonate chain, a diol having a sulfonic acid group, a diamine, a diisocyanate, and the like with a diisocyanate in a solvent. Thereafter, it can be produced by emulsification.

Examples of the polycarbonate polyol include compounds obtained by reacting glycols such as 1,4-butanediol, 1,6-hexanediol, diethylene glycol and the like with diphenyl carbonate and phosgene. These can be used alone or in combination of two or more.

Examples of the diisocyanate include 2,4-tolylene diisocyanate, 2,6-tolylene diisocyanate, m-phenylene diisocyanate, p-phenylene diisocyanate, 4,4′-diphenylmethane diisocyanate, 2,4′-diphenylmethane diisocyanate, 2 , 2'-diphenylmethane diisocyanate, 3,3'-dimethyl-4,4'-biphenylene diisocyanate, 3,3'-dichloro-4,4'-biphenylene diisocyanate, 1,5-naphthalene diisocyanate, 1,5-tetrahydronaphthalene Diisocyanate, tetramethylene diisocyanate, 1,6-hexamethylene diisocyanate, dodecamethylene diisocyanate, trimethylhexamethylene diisocyanate, 1,3-cyclohexylene Diisocyanate, 1,4-cyclohexylene diisocyanate, xylylene diisocyanate, hydrogenated xylylene diisocyanate, lysine diisocyanate, isophorone diisocyanate, 4,4'-dicyclohexylmethane diisocyanate, 3,3'-dimethyl-4,4'-dicyclohexylmethane diisocyanate Etc., and can be used alone or in combination of two or more.

Of the above-mentioned diisocyanates, aliphatic diisocyanates are preferred from the viewpoints of stability and light resistance. As the aliphatic diisocyanate, among the diisocyanates listed above, those belonging to the aliphatic diisocyanate can be used as they are.

Examples of the polyester polyol include polyesters obtained by dehydration condensation reaction from alcohols and acid components, polyesters obtained by ring-opening polymerization reaction of cyclic ester compounds such as ε-caprolactone, and copolyesters thereof.

Examples of alcohols used for producing the polyester polyol include ethylene glycol, propylene glycol, 1,3-propanediol, 1,4-butanediol, 1,5-pentanediol, 1,6- Hexanediol, neopentyl glycol, diethylene glycol, triethylene glycol, tetraethylene glycol, polyethylene glycol, dipropylene glycol, tripropylene glycol, bishydroxyethoxybenzene, 1,4-cyclohexanediol, 1,4-cyclohexanedimethanol, bisphenol A And glycol components such as hydrogenated bisphenol A, hydroquinone and their alkylene oxide adducts.

Examples of the acid component used for producing the polyester polyol include succinic acid, adipic acid, azelaic acid, sebacic acid, dodecanedicarboxylic acid, maleic anhydride, fumaric acid, and 1,3-cyclopentanedicarboxylic acid. 1,4-cyclohexanedicarboxylic acid, terephthalic acid, isophthalic acid, phthalic acid, 1,4-naphthalenedicarboxylic acid, 2,5-naphthalenedicarboxylic acid, 2,6-naphthalenedicarboxylic acid, naphthalic acid, biphenyldicarboxylic acid, 1 , 2-bis (phenoxy) ethane-p, p'-dicarboxylic acid and anhydrides or ester-forming derivatives of these dicarboxylic acids; p-hydroxybenzoic acid, p- (2-hydroxyethoxy) benzoic acid and their hydroxycarboxylic acids Examples include acids.

As the polyol used to produce the polyurethane resin emulsion, in addition to the polycarbonate polyol and polyester polyol, polyols other than these can be used. Examples of polyols other than the above include polyols having an alkylene oxide chain. Typical examples of the alkylene oxide chain include ethylene oxide, propylene oxide, ethylene oxide adducts of bisphenol, and the like, and these may be used alone or in combination of two or more. Although there is no restriction | limiting in particular in content of an alkylene oxide chain, Generally, the mechanical strength of a membrane | film | coat will be a practical level by using together with another polyol component.

Examples of commercially available polyurethane resin emulsions containing a polycarbonate chain in the above molecule include “Pateracol” (trade name), “Bondic” (trade name), and “Hydran” manufactured by Dainippon Ink & Chemicals, Inc. (Trade name) and “Imperil” (trade name) manufactured by Bayer.

  The average particle size of the polyurethane resin emulsion is preferably 3.0 μm or less from the viewpoint of transparency, stability and water resistance of the resin emulsion. Moreover, said polyurethane-type resin is mix | blended so that it may become 40-70 mass% normally in solid content in said all water-insoluble resin, Preferably it is 50-60 mass%. If it is less than 40% by mass, the water permeability of the ink receiving layer due to the interaction with PVA or the like cannot be sufficiently suppressed. On the other hand, when it exceeds 70% by mass, the PVA or the like is excessively deteriorated, the water absorption of the ink receiving layer is lowered, and the ink after printing remains on the surface, and color is liable to occur.

Examples of the water-insoluble resin other than the polyurethane resin include acrylic or methacrylic resins, vinyl chloride resins, vinyl chloride-vinyl acetate copolymers, vinyl acetate resins, butyral resins, alkyd resins, and polyester resins. , Polycarbonate resins, styrene-acrylic resins, and the like. Among them, vinyl acetate resins are preferable and those having a polymerization degree of 300 to 10,000 are preferable in terms of film strength and color developability of the ink receiving layer.

Specific examples of the vinyl acetate resin include, for example, polyvinyl acetate, vinyl acetate-acrylic acid ester copolymer, vinyl acetate-ethylene copolymer, vinyl acetate-maleic acid diester copolymer, vinyl acetate- Examples include acrylic acid copolymers, vinyl acetate-crotonic acid copolymers, and vinyl acetate-maleic anhydride copolymers.

The average particle diameter of the aqueous emulsion, which is a form when a water-insoluble resin other than the polyurethane-based resin is blended, is preferably 3.0 μm or less from the viewpoint of transparency, stability and water resistance of the resin emulsion. When the particle diameter exceeds 3.0 μm, water resistance, stability, transparency, printing gloss and the like tend to be slightly inferior. Moreover, water-insoluble resin other than this polyurethane type is mix | blended so that it may become 30-60 mass% in total water-insoluble resin, Preferably, it is 40-50 mass%.

The water-soluble resin is composed of PVP, PVA, and the like, and is 25 to 45% by mass, preferably 30 to 40% by mass, out of a total of 100 parts by mass of the water-soluble resin and the water-insoluble resin constituting the ink receiving layer. %. Both the above PVP and PVA are hydrophilic resins. Among them, PVP has an extremely excellent ink liquid absorbability, and plays a role of absorbing a large amount of ink discharged from an inkjet head quickly. I'm in charge. PVA and the like are water-absorbing and play a role as a binder for the ink receiving layer. In the present invention, after printing on the inkjet recording sheet of the present invention, for example, on the surface thereof. At the peripheral edge of the ink receiving layer when both surfaces are sandwiched between water-resistant layers, such as when applied to a water-resistant floor surface through an adhesive layer formed by attaching a double-sided adhesive sheet, PVA, etc. , It absorbs water and swells itself, and on the other hand, it is altered by the interaction with the water-insoluble polyurethane resin used together, and as a result, water substantially penetrates into the central part of the ink receiving layer. This is effective in blocking the ink receiving layer image and preventing the ink receiving layer from peeling off.

Said PVP is normally 30 to 70 mass% of said water-soluble resin, Preferably it is 40 to 60 mass%. If it is less than 30% by mass, the ink absorption of the ink receiving layer is insufficient, and if it exceeds 70% by mass, the proportion of PVA or the like decreases, and ink jet reception due to interaction with the urethane resin used in combination. The water permeability of the layer cannot be sufficiently suppressed. Further, as the PVA, those having water absorption and edge water penetration prevention properties are used, and specifically, PVA, modified PVA such as cationized PVA and PVA introduced with a carboxyl group are used. Alternatively, both partially saponified PVA and fully saponified PVA can be used. At that time, the mass average degree of polymerization of PVA or the like is 1000 or more, preferably 1500 or more in order to exhibit sufficient water resistance. Such PVA etc. are mix | blended 30-70 mass% in water-soluble resin, Preferably 40-60 mass% is mix | blended.

Examples of the inorganic pigment include kaolin, talc, light calcium carbonate, heavy calcium carbonate, satin white, aluminum silicate, calcium silicate, magnesium silicate, synthetic amorphous silica, aluminum hydroxide, alumina, lithopone, zeolite, Examples thereof include pigments such as synthetic smectite, magnesium carbonate, and magnesium hydroxide. Usually, white pigments are used, and porous synthetic amorphous silica is particularly preferable.

The particle size of the inorganic pigment is usually 6 to 10 μm as an average particle size (mass average), and preferably 7 to 9 μm. Among them, those having a wide particle size distribution of the particle group are preferable, for example, those containing 20% by mass or more of particles (small particles) having a particle size of 6 μm or less and 20% by mass or more of particles (large particles) having a particle size of 10 μm or more. preferable. Such a distribution can be configured, for example, by blending a particle group having an average particle diameter of 6 μm or less and a particle group having an average particle diameter of 10 μm or more. If the large particles are less than 20% by mass, the ink absorbability is insufficient, and if the small particles are less than 20% by mass, the large particles are large and the edge water permeation preventing property is lowered. When the large particles and the small particles are, for example, synthetic amorphous silica, the above large particles are Mizukasil P78D (average particle size: 12 μm, manufactured by Mizusawa Chemical Co., Ltd.), and the above small particles are Silysia 435 ( An average flow rate of 4 μm, a product manufactured by Fuji Silysia Chemical Ltd.) is commercially available. In order to improve the effect of preventing the ink from bleeding, it is more preferable that the pigment has a surface treated with magnesium ions, such as the above-mentioned silicia 435. The inorganic pigment is usually blended in an amount of 50 to 100 parts by mass, preferably 60 to 90 parts by mass with respect to 100 parts by mass of the water-soluble resin and the water-insoluble resin.

The water-soluble magnesium salt is added in order to further improve the ink bleeding prevention property of the ink receiving layer. Examples of the magnesium salt include magnesium chloride, magnesium sulfate, magnesium nitrate, magnesium lactate, and magnesium acetate, among which magnesium chloride can be preferably used. The mixing ratio of the water-soluble magnesium salt is usually 2 to 20 parts by mass in terms of anhydrous salt, and practically 3 to 15 parts per 100 parts by mass of the water-soluble resin and the water-insoluble resin. Part by mass.

The ink-receiving layer coating solution includes the water-insoluble resin emulsion (water-insoluble resin emulsion containing an aqueous polyurethane resin emulsion as an essential component), water-soluble resin (PVP, PVA, etc.), inorganic pigment, and water-soluble magnesium salt. Is dissolved and / or dispersed in an aqueous solvent. Although the density | concentration of said coating liquid is not specifically limited, Usually, it is 10-30 mass% as solid content concentration, and is 12-25 mass% practically.

  The above-mentioned aqueous solvent is mainly composed of water, and an organic solvent is appropriately blended depending on the components to be blended. Such an organic solvent is not particularly limited, but an organic solvent such as methanol or isopropyl alcohol is preferably used in consideration of the environment of the process. The kind and blending ratio of the organic solvent are appropriately set depending on the kind and amount of the resin component to be added.

In preparing the ink-receiving layer coating liquid, it is preferable that a relatively poorly soluble material such as PVA is separately dissolved in a solvent before blending with other components. Similarly, an inorganic pigment such as synthetic amorphous silica is preferably added to an aqueous solvent and well dispersed using a homomixer or the like before blending into the ink receiving layer coating solution. At this time, the dispersed inorganic pigment tends to settle over time, and once settled, it is difficult to recover to a preferable dispersed state even if it is stirred and dispersed again. Such a sedimentation phenomenon is particularly likely to occur when the concentration of PVP, PVA or the like is low. In order to improve the dispersion stability of the inorganic pigment, it is preferable that calcium carbonate fine particles, which are also one of the inorganic pigments, coexist when the inorganic pigment is dispersed. The added amount of the calcium carbonate fine particles is usually 3 to 15 parts by mass of the inorganic pigment, and is practically 3 to 10 parts by mass.

The above ink-receptive layer coating liquid may contain other pigment dispersants, inorganic and synthetic resin beads, colored pigments, antioxidants, ultraviolet absorbers, fluorescents, as long as they do not contradict the spirit of the present invention. Other additives such as brighteners and plasticizers can be added as appropriate.

  The ink receiving layer coating liquid can be applied to the substrate sheet surface by a known method. For example, a bar coater, an air knife coater, a blade coater, a roll coater, a gravure coater, a micro gravure coater, a fan. Ten reverse coaters, spray coaters, curtain coaters, comma coaters and the like can be used. The coating amount applied in this manner is usually 15 to 40 μm, and practically 20 to 30 μm, as the thickness after drying.

In addition, the method for drying the ink receiving layer coating liquid is any drying method as long as the organic solvent is sufficiently evaporated and a film is formed without causing any trouble such as thermal deterioration of the base material. For example, a hot air drying furnace, a drying drum, or the like can be used. The temperature of the hot air is, for example, 80 to 120 ° C.

  The ink jet recording sheet of the present invention obtained as described above can be used for an ink jet printer as it is to produce a print sheet having excellent printability and water resistance. When an acrylic pressure-sensitive adhesive layer is formed on the ink receiving layer by bonding a double-sided pressure-sensitive adhesive sheet, such as when laminating the floor material to produce a flooring with an image pattern, bonding with the pressure-sensitive adhesive In order to improve the properties, it is preferable to coat the surface of the ink receiving layer with an overcoat layer. Examples of the resin component constituting the overcoat layer include polystyrene resin, acrylonitrile / butylene / styrene resin, acrylic cationic resin, acrylic urethane resin, nitrile rubber / phenol resin, and commercially available products such as saftomer. (Trade name, main component is acrylic cationic resin, manufactured by Soken Chemical Co., Ltd.), vinylol 2400 (trade name, main component is nitrile rubber / phenol resin, Showa High Polymer Co., Ltd.), and the like.

The overcoat layer is formed by dissolving the resin component in a suitable organic solvent to form a 1 to 5% by weight diluted coating solution, and applying and drying. When the resin component is vinylol 2400, a mixed solvent of methyl ethyl ketone, methyl isobutyl ketone and diacetone alcohol is used as the organic solvent. The method of applying the overcoat layer coating solution can be performed by a known method, and for example, can be performed by a gravure coater, a micro gravure coater, a spray coater, or the like. The coating amount of the overcoat layer as coating amount after drying, typically, 0.05 to 1.0 g / ^{m 2,} in practical, are 0.1 to 0.5 g / ^{m 2.}

  The adhesive used to attach the printed sheet obtained by printing on the inkjet recording sheet of the present invention to a flooring or the like is not particularly limited as long as it is water-resistant, but the above-mentioned overcoat layer is not limited. When nitrile rubber / phenolic resin is used, a commercially available acrylic pressure-sensitive adhesive can be suitably used as the pressure-sensitive adhesive. In particular, a double-sided pressure-sensitive adhesive sheet obtained by applying both sides of an acrylic pressure-sensitive adhesive to a white base material can be suitably used. As such a white substrate, a white PET film formed by kneading a white pigment such as titanium oxide in polyethylene terephthalate is preferable. Examples of commercially available products include Lumirror 50E20 and Lumirror 75E20 (trade name, manufactured by Toray Industries, Inc.). White PET is bonded to an ink receiving layer printed by an ink jet printer after applying an adhesive, and thereby has an effect of obtaining a clear and high-contrast printed image. The acrylic pressure-sensitive adhesive to be applied to both sides can be a commercially available one, but the adhesive on the side to be bonded to the ink receiving layer is transparent or white to obtain the above-mentioned clear and high-contrast image. Preferred above. As the double-sided pressure-sensitive adhesive sheet, for example, a white PET film FD-AD1000 (trade name: AD film for footprint, released by Sakurai Co., Ltd.) coated with an acrylic pressure-sensitive adhesive on both sides is commercially available.

Hereinafter, the present invention will be specifically described with reference to examples and comparative examples, but the present invention is not limited to the following examples. In addition, the part and% in an example show a mass part and mass%, respectively. In addition, the ink jet recording sheets obtained in the examples and comparative examples were evaluated for edge water penetration prevention during printing, ink bleeding, ink color appearance, ink stickiness, and curling by the following methods. The printing process was carried out using an exclusive aqueous pigment ink in an Mimaki ink jet printer (JV22-130 type).

(End water penetration prevention)
About the obtained ink jet recording sheet, a landscape photographic image is printed in full color (mirror printing of the target image) on the entire surface of the ink receiving layer to obtain a printing sheet. After 24 hours, both sides of the adhesive are coated with an acrylic adhesive. The white PET film and FD-AD1000 (trade name: AD film for footprints, released by Sakurai Co., Ltd.) coated on the surface are laminated with the one side of the release paper that is not laminated, and pasted with a laminator set at a roll temperature of 40 ° C. Combined to obtain a printed sheet with a pressure-sensitive adhesive layer, cut a square of 20 cm per side from the printed sheet with the pressure-sensitive adhesive layer, peeled off the release sheet, and exposed this to the floor plate instead of the adhesive layer It was attached to a square acrylic plate having a thickness of 5 mm and a side of 30 cm. This was placed in a vat with a depth of 50 mm, and an acidic dye Neolan Black 0.01% aqueous solution was poured into the vat so that the depth was 30 mm, left at room temperature for 48 hours, and then taken out. After lightly washing the surface with water, observe the penetration of the dye from the edge of the printed sheet to evaluate the water penetration prevention at the edge. The case where it was less than “○” was assigned.

(Ink bleeding)
About the obtained ink jet recording sheet, a test chart in which line widths of 0.1 mm, 0.2 mm, and 0.5 mm are formed into a vertical and horizontal grid pattern for cyan, magenta, yellow, and black inks of the aqueous pigment ink, 5 minutes after printing, use a 10X magnifying glass to see if there is a wrinkle-like bleed from each line. The case where it was not performed was set as “◯”.

(Ink color)
The ink jet recording sheet thus obtained was printed in purple with a cyan ink and a magenta ink overlaid (rectangular with a length of 20 mm and a width of 10 mm), and after 10 minutes, a PET film having a thickness of 75 μm was added to the above: After overlapping (made by Toyobo Co., Ltd.) and pressing with your fingertips, peel off the PET film, observe the contact surface of the PET film, "X" if the ink is colored, the film surface is completely contaminated The case where it was not done was set as “◯”.

(Ink stickiness)
When the fingertip is cleaned with alcohol-impregnated gauze and dried well, the fingertip is printed, pressed against the printed surface after 10 minutes, and then felt as if it was pulled by stickiness when pulled away. The case was judged as “◯”.

(Curl occurrence)
Cut 20cm square part from inkjet recording sheet before printing to make a test piece, place it on a flat glass plate, and measure the degree of lifting due to curl at the four corners after 5 hours in an environment of 25 ° C x 60% RH Observation was made, and when the maximum lifting height was less than 10 mm, “◯” was evaluated, and when it was 10 mm or more, “×” was evaluated. At this time, in preparation for the case where the curl directions at the four corners are directed downward, a test piece having an upside down orientation was also prepared.

[Example 1]
(Preparation of silica fine particle dispersion)
First, in a mixed solvent consisting of 155 parts of ion-exchanged water and 18 parts of IPA (isopropyl alcohol), 20 parts of synthetic amorphous silica fine particles having an average particle diameter of 12 μm (Mizukasil P78D, manufactured by Mizusawa Chemical Co., Ltd.), average particle diameter Is charged with 20 parts of synthetic amorphous silica fine particles (Silicia 435, manufactured by Fuji Silysia Chemical Ltd.) and 6 parts of calcium carbonate having an average particle size of 1.5 μm, and 6000 rpm using a homomixer. For 10 minutes. Next, 31 parts of IPA was added and further dispersed at 6000 rpm for 10 minutes using a homomixer to obtain a silica fine particle dispersion.

(Preparation of coating solution for ink receiving layer)
To 375 parts of the above-mentioned silica fine particle dispersion, 75 parts of Rubitek K90 (trade name, BASF Japan sale, polyvinylpyrrolidone 20% aqueous solution) and 8% aqueous solution of PVA235 (trade name, manufactured by Kuraray Co., Ltd., PVA modified product) 188 parts, Pateracol IJ-26 (: trade name, manufactured by Dainippon Ink Co., Ltd., aqueous polyurethane resin emulsion, solid content 15%), 280 parts, Polysol AM3000 (: trade name, manufactured by Showa Polymer Co., Ltd., acetic acid) 50 parts of a 56% aqueous solution of vinyl-ethylene copolymer), 50 parts of a 20% magnesium chloride (anhydrous salt equivalent) aqueous solution and 8 parts of a 67% aqueous solution of methanol, and 10 minutes at 6000 rpm using a homomixer. An ink receiving layer coating liquid having a solid content of about 17.4% was obtained by dispersion.

As a base sheet, a Mayer bar with a 1.8 mm wire on the non-hard-coated surface of Ray Hyper VC01 (Released by: Tokyo Nakai Shoji Co., Ltd.) hard-coated on one side of a 100 μm thick polyester film The ink receiving layer coating solution was applied so that the thickness after drying was 25 μm and dried in hot air at 110 ° C. for 3 minutes to obtain the ink receiving layer of the present invention.

(Preparation of overcoat layer coating solution)
Separately, 40 parts of vinylol 2400 was added and dissolved in a mixed solvent of 55 parts of methyl ethyl ketone, 55 parts of methyl isobutyl ketone and 55 parts of diacetylacetone to obtain an overcoat layer coating solution.

The overcoat layer coating solution is applied to the surface of the receiving layer of the inkjet recording sheet using a Mayer bar with 0.1 mm wire, so that the coating amount after drying is 0.5 g / m ^2. And dried in hot air at 100 ° C. to coat the overcoat layer, thereby obtaining the ink jet recording sheet of the present invention.

The obtained ink jet recording sheet was evaluated for edge water permeation prevention, bleeding at the time of printing, ink color appearance, ink stickiness and curling properties by the above-described evaluation methods, and the results were the main components of the receiving layer. Table 1 shows the composition.

[Example 2]
In the preparation of the coating solution for ink-receiving layer of Example 1, the amount of each component added was changed to 100 parts for Rubitec K90, 250 parts for PVA235, 240 parts for Pateracol IJ-26, and 43 parts for Polysol AM3000. Was the same as in Example 1 to obtain an ink jet recording sheet of the present invention. The obtained ink jet recording sheet was evaluated for edge water permeation prevention, bleeding at the time of printing, ink color appearance, ink stickiness and curling properties by the above-described evaluation methods, and the results were the main components of the receiving layer. Table 1 shows the composition.

[Example 3]
In the preparation of the silica fine particle dispersion of Example 1, instead of 20 parts of synthetic amorphous silica fine particles having an average particle diameter of 12 μm and 20 parts of synthetic amorphous silica fine particles having a surface having an average particle diameter of 4 μm treated with magnesium ions, A silica fine particle dispersion was obtained in the same manner as in Example 1 except that only 53.3 parts of synthetic amorphous silica fine particles having an average density of 8 μm (Mizukasil P-709, manufactured by Mizusawa Chemical Co., Ltd.) were used. It was. In addition, in the preparation of the ink receiving layer coating liquid of Example 1, 395 parts of the silica fine particle dispersion, 90 parts of Rubitec K90, 150 parts of PVA235, and Pateracol IJ-26 were added. An ink jet recording sheet of the present invention was obtained in exactly the same manner as in Example 1 except that 187 parts and polysol AM3000 were changed to 75 parts. The obtained ink jet recording sheet was evaluated for edge water permeation prevention, bleeding at the time of printing, ink color appearance, ink stickiness and curling properties by the above-described evaluation methods, and the results together with the component composition of the receiving layer. It is shown in Table 1.

[Comparative Example 1]
In the preparation of the ink-receiving layer coating liquid of Example 1, among the added amounts of each component, 150 parts for Rubitec K90, 375 parts for PVA235, 160 parts for Pateracol IJ-26, and 28.6 parts for Polysol AM3000 were changed. Except that, an ink jet recording sheet of the present invention was obtained in exactly the same manner as in Example 1. The obtained ink jet recording sheet was evaluated for edge water permeation prevention, bleeding at the time of printing, ink color appearance, ink stickiness and curling properties by the above-described evaluation methods, and the results were the main components of the receiving layer. Table 1 shows the composition.

[Comparative Example 2]
In the preparation of the ink-receiving layer coating liquid of Example 1, the amount of each component added was changed to 50 parts for Rubitec K90, 125 parts for PVA235, 320 parts for Pateracol IJ-26, and 57 parts for Polysol AM3000. Was the same as in Example 1 to obtain an ink jet recording sheet of the present invention. The obtained ink jet recording sheet was evaluated for edge water permeation prevention, bleeding at the time of printing, ink color appearance, ink stickiness and curling properties by the above-described evaluation methods, and the results were the main components of the receiving layer. Table 1 shows the composition.

[Comparative Example 3]
In the preparation of the ink-receiving layer coating liquid of Example 1, the addition amount of each component was changed to 30 parts for Rubitec K90, 300 parts for PVA235, 280 parts for Pateracol IJ-26, and 50 parts for Polysol AM3000. Was the same as in Example 1 to obtain an ink jet recording sheet of the present invention. The obtained ink jet recording sheet was evaluated for edge water permeation prevention, bleeding at the time of printing, ink color appearance, ink stickiness and curling properties by the above-described evaluation methods, and the results were the main components of the receiving layer. Table 1 shows the composition.

[Comparative Example 4]
In the preparation of the ink-receiving layer coating liquid of Example 1, among the addition amounts of each component, 75 parts for Rubitec K90, 188 parts for PVA235, 93.3 parts for Pateracol IJ-26, and 100 parts for Polysol AM3000 were changed. Except that, an ink jet recording sheet of the present invention was obtained in exactly the same manner as in Example 1. The obtained ink jet recording sheet was evaluated for edge water permeation prevention, bleeding at the time of printing, ink color appearance, ink stickiness and curling properties by the above-described evaluation methods, and the results were the main components of the receiving layer. Table 1 shows the composition.

[Comparative Example 5]
In the preparation of the silica fine particle dispersion of Example 1, 10 parts of synthetic amorphous silica fine particles having an average particle diameter of 12 μm and 10 parts of synthetic amorphous silica fine particles having a surface having an average particle diameter of 4 μm treated with magnesium ions were added to 10 parts. A silica fine particle dispersion was obtained in the same manner as in Example 1 except for the change. Further, in the preparation of the ink-receiving layer coating liquid of Example 1, the silica fine particle dispersion was changed to 330 parts of the added amount of each component. An ink jet recording sheet was obtained. The obtained ink jet recording sheet was evaluated for edge water permeation prevention, bleeding at the time of printing, ink color appearance, ink stickiness and curling properties by the above-described evaluation methods, and the results were the main components of the receiving layer. Table 1 shows the composition.

[Comparative Example 6]
In Example 1, an ink jet recording sheet of the present invention was obtained in the same manner as in Example 1 except that water-soluble magnesium was not added. The obtained ink jet recording sheet was evaluated for edge water permeation prevention, bleeding at the time of printing, ink color appearance, ink stickiness and curling properties by the above-described evaluation methods, and the results were the main components of the receiving layer. Table 1 shows the composition.

[Comparative Example 7]
A silica fine particle dispersion was prepared without adding the calcium carbonate fine particles used together when preparing the silica fine particle dispersion in Example 1, and a coating liquid for an ink receiving layer was prepared using this silica fine particle dispersion. 100 ml of the receiving layer coating solution and the ink receiving layer coating solution prepared in Example 1 were each poured into a 100 ml graduated cylinder and allowed to stand for 24 hours, and then the suspension stability of silica particles in each coating solution was observed. As a result, only when the calcium carbonate fine particles were not added, the silica particles had settled down to a portion of about 15 cc scale.

The ink jet recording sheet of the present invention is excellent in printability when an image is ink jet printed thereon. In particular, when a water resistant base sheet is used as the base sheet, the ink receiving layer of the print sheet is used. When affixed to a water-resistant floor surface through an adhesive layer formed by, for example, laminating a double-sided pressure-sensitive adhesive sheet on the surface, water spilled on the floor or water during floor cleaning is in contact with the peripheral edge of the printed sheet. However, since the edge water penetration preventing property is excellent, the bleeding of the image of the ink receiving layer and the peeling of the ink receiving layer do not occur.
As a result, it can be used as a decoration for flooring images or as an advertising medium, and a comfortable space can be provided from the aspect of living environment or from the commercial aspect by widely decorating the water-resistant floor surface. It has a great industrial applicability.

Explanatory drawing of the layer constitution of the ink jet recording sheet of Example 1 Explanatory drawing of the layer structure of the flooring which laminated | stacked the sheet | seat for inkjet recording of Example 1. FIG.

Explanation of symbols

1: Hard coat layer 2: Substrate sheet 3: Ink receiving layer 4: Overcoat layer 5: Adhesive layer 6: Floor material

Claims (10)

In the ink jet recording sheet in which an ink receiving layer is provided on a base sheet, 55 to 75 parts by mass of a water-insoluble resin containing 40 to 70% by mass of a polyurethane-based resin as an essential component is included in the ink receiving layer. , 50 to 100 parts by mass of an inorganic pigment with respect to 100 parts by mass of 25 to 45 parts by mass of a water-soluble resin containing 30 to 70% by mass of polyvinyl alcohol and / or a modified product thereof and 70 to 30% by mass of polyvinyl pyrrolidone. And 2 to 20 parts by mass of a water-soluble magnesium salt (anhydrous salt equivalent). 2. The ink jet recording sheet according to claim 1, wherein the base sheet is water resistant and transparent. 3. The ink jet recording sheet according to claim 1, wherein the inorganic pigment is synthetic amorphous silica. The ink jet recording sheet according to any one of claims 1 to 3, wherein the inorganic pigment component contains 3 to 15 parts by mass of calcium carbonate fine particles. The inkjet recording sheet according to any one of claims 1 to 4, wherein the water-soluble magnesium salt is magnesium chloride. The inkjet recording sheet according to any one of claims 1 to 5, wherein the polyurethane resin is a polyurethane resin emulsion containing a polycarbonate chain in the molecule. The ink jet recording sheet according to any one of claims 1 to 6, wherein an overcoat layer mainly composed of a water-insoluble resin is coated on the surface of the receiving layer. 8. The ink jet recording sheet according to claim 1, wherein a surface of the base sheet opposite to the surface on which the ink receiving layer is laminated is hard-coated. In the ink jet recording sheet according to any one of claims 1 to 8, the base sheet is transparent, and after printing an image on the ink receiving layer, an adhesive layer is formed on the printing surface, A method for using an ink jet recording sheet, comprising adhering to a surface of an article to decorate the article surface. A sheet for ink-jet recording according to any one of claims 1 to 8, and a transparent or layer for printing on the ink-receiving layer of the sheet for ink-jet recording and then laminating on the printed surface to impart tackiness A kit with a double-sided pressure-sensitive adhesive sheet laminated with a white pressure-sensitive adhesive layer.

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